Cell phones are becoming a contraband problem in Texas prisons, leaving authorities to worry they may be used to plot escapes or conduct criminal business behind bars. Last year, investigators seized 135 cell phones and through mid-April, the number this year was 90. While other contraband items are seized more often, phones have become extremely valuable to prisoners who can sell minutes to other inmates.

"It's just like American Express it's good as cash," said John Moriarty, inspector general of the Texas Department of Criminal Justice.

Investigators say prisoners are willing to pay between $350 and $600 to have a phone smuggled into prison. And they often involve a corrections officer in such schemes. Two years ago, investigators arrested a corrections officer who offered to smuggle a cell phone and heroin into the Darrington Unit in Brazoria County. She wanted $200 for the phone and $50 for the drugs.

"With a cell phone you can arrange other things," Tim English, an investigator for the inspector general, told The Dallas Morning News in today's editions. "That's the beauty of the cellphone you have access to the outside world."

Inmates prefer prepaid phones that don't require a user to provide a name or account number to a wireless provider. Memory cards are kept separate, minimizing the loss in case a phone is seized.

The Texas prison cell phone problem is highly concentrated in two prisons the Darrington Unit and Connally Unit in Karnes County where prosecutors say gang membership is high. Investigators are looking at new technology that would jam cell phone signals, but are wary of using it near highly populated areas, where it could block legitimate calls. The Federal Communications Commission says it is illegal to jam or disrupt wireless communications.

But some defense attorneys say prosecutors haven't proven cell phones are used for anything more than getting in touch with family. Texas prisons don't have pay phones, so offenders are desperate to communicate.

"Drugs take you out of the prison psychologically," said David P. O'Neil, a defense attorney in Huntsville and former director of the prison system's public defender's office. "Phones place you outside the prison in a different sense. There is a premium on escaping in that sense."